Rats: some people enjoy their company as pets, to many others, they are virulent pests that helped the spread of the bubonic plague ("black death") in Medieval Europe. For New Yorkers, they are just one of many interesting local daily sights on the subway tracks and platforms. I can tell you from experience (source: I live in New York City) that they often seem healthier and in better spirits than many of the humans that call this fair city home. Yet it turns out some of them are carrying a surprising number of previously undocumented viruses, according to the results of a study of the Big Apple's rodents published today in the journal mBio and reported by The New York Times.

Specifically, scientists captured 133 rats from traps set in five locations around New York City, euthanized them, then took genetic samples of the bacteria and viral specimens found in their tissues and excretions (saliva, feces, etc). The scientists found lots of viruses, not surprisingly. But while many of the bacteria detected were expected — including e. coli and salmonella — the scientists also found at 18 completely new viruses. None of these new viruses have been found in humans, at least not yet, but two of them are structurally similar to Hepatitis C, which does occur in people and raises the risk of liver scarring and cancer. While there's no immediate cause for alarm, the scientists note that that the spread of these new viruses from rats to humans could theoretically already be occurring and is possible in the future, and are advocating for more comprehensive disease monitoring in humans. Something to think about the next time you're waiting for the downtown F train.